. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . tubes takes place. In eachof the tiny sections of the indicator,corresponding to an actual signal sys-tem block, there are two small electricbulbs. One of these bulbs is encased inred glass and the other is encased in greenglass. Suitable electric connection ismade with the track circuit which oper-ates the signals, so that when the tun- section, proves that the train is out. The whole arrangement appears onthe face of it to be simplicity itself, andlike most other effective devices it is ina
. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . tubes takes place. In eachof the tiny sections of the indicator,corresponding to an actual signal sys-tem block, there are two small electricbulbs. One of these bulbs is encased inred glass and the other is encased in greenglass. Suitable electric connection ismade with the track circuit which oper-ates the signals, so that when the tun- section, proves that the train is out. The whole arrangement appears onthe face of it to be simplicity itself, andlike most other effective devices it is ina sense quite simple, but there aresome details which have been workedout in connection with the devicewhich have required considerable skilland judgment. The ordinary track cir-cuit carries an alternating current ofabout 7 volts. This current operatesan A. C. relay which governs themovement of a direct current relay,which opens and closes a D. C. direct current is used to oper-ate the electro-pneumatic mechanismwhich moves the automatic stop ateach of the signals. On this D. C. cir-. INTERBOROUGH TUNNEL INDICATOR. DARK SECTIONS SHOW BLOCKS OCCUPIED BY TRAINS.(Small white offset lines show telephone stations; longer white vertical lines show positions of signals.) patchers office gives visible announce-ment of the position of any train whichenters the tubes as it makes its wayunder the waters separating the twocities. The indicator is a box about 2 ft. 6ins. long by 12 ins. high and 9 This box is supported on a suit-able stand and has a muffed glass front,on which is drawn a miniature repre-sentation of the tubes, which consistsof two illuminated bands each half aninch wide, which dip and rise in ac-cordance with the grades of the tunnel,and along which are marked, at ac-curately scaled distances, the signals,the telephone stations and the ventilat-ing shafts. The upper band of lightrepresents the south tube, throughwhich the traffic ex New York passes,an
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1901
